Airport officials on Monday said around 650 flights are set to be cancelled at Berlin’s two commercial airports, as about 2,000 ground crew workers stage another strike in a dispute over pay.

The walkout began at 4 a.m. (0300 GMT) and is set to last until 5 a.m. the following day.

It affects both of the German capital’s airports in Schoenefeld in the south-east and Tegel in the north-west.

A spokesman for the two airports told dpa that at Tegel, at least 448 flights are expected to stay grounded, while at Schoenefeld, 194 flights are due to be cancelled.

“We are asking all passengers to check with their airline, about the status of their flight, before they start their trip,” a statement on a website for the airports said.

Berlin’s mayor Michael Mueller, who was due to make a three-day trip to Moscow, had his journey interrupted.

The city has organised replacement flights for the mayor via Dresden airport.

Some airlines will re-route some flights to the eastern German cities of Dresden and Leipzig, with the airports taking on 25 extra flights each.

Airport officials expect Monday’s strikes could cause flight disruptions into Tuesday.

An earlier strike on Friday caused hundreds of flight cancellations.

Trade union Verdi is pushing for a pay increase and better working hours for its members, arguing that their workload is increasing with the growing number of passengers and a greater focus on security.

Negotiators were unable to come to a deal, making a renewed strike on Monday inevitable, the union said.

Verdi is demanding a 1-euro (1.07-dollar) hourly wage increase over the course of one year.

The airports have offered that amount over a three-year period, capped at an eight-per-cent raise.